Cambridge O Level Computer Science · Syllabus 2210 · Automated and Emerging Technologies
Rule Base
What is Rule Base?
The component of an expert system that stores the rules, commonly represented as IF-THEN rules, which state what conclusion follows from a given combination of facts.
This definition is part of the Automated and Emerging Technologies chapter in Cambridge O Level Computer Science.
Rule Base in context
An expert system is an AI system that reproduces the decision-making of a human expert within one narrow domain. The syllabus specifies exactly four components: a knowledge base, a rule base, an inference engine and an interface. The knowledge base stores facts about the domain; the rule base stores the rules that say what follows from those facts; the inference engine applies the rules to the information supplied and reasons towards a conclusion; and the interface is how the user and the system communicate. Learn all four names and one sentence for each — the syllabus names exactly these four.
Common mistakes with Rule Base
- M19. “An expert system and machine learning are basically the same thing.” Why wrong They differ in where the decision-making comes from: an expert system applies rules a person wrote down; machine learning applies a model the program derived from data. Say instead “In an expert system a specialist writes the rules into the rule base. In machine learning the program finds patterns in example data and builds the model itself.”
- M20. “The knowledge base and the rule base are the same component — and the inference engine stores the knowledge.” Why wrong Three separate components are being merged. The knowledge base holds facts; the rule base holds the rules that draw conclusions from facts; the inference engine holds neither — it is the reasoning process that consults both. Say instead “The inference engine searches the rule base for rules whose conditions the supplied facts satisfy, and applies them using knowledge from the knowledge base.”
Questions students ask about Rule Base
What is the difference between the knowledge base and the rule base?
The knowledge base holds the facts and expert knowledge about the domain — what is true. The rule base holds the rules, commonly written as IF … THEN, that say what conclusion follows from a combination of facts — what may be concluded. They are listed separately in the syllabus, so merging them in an answer cannot earn both marks.